Communications networks allow electronic communications devices to transmit and receive data over physical media. Some networks use a dedicated medium such as twisted-pair wire, while others use media such as coaxial cable or power lines shared with other systems, and even others are wireless systems using radio frequency (RF) signals or other wireless signals. These networks all allow some form of point-to-point communication between devices or stations, often with intermediate junctions such as hubs, routers, and base stations.